Okay all you Li-ion battery experts, I have a question for you.
For a number of reasons I am using Internet-sharing from my phone via Wi-Fi as my main home Internet connection. My phone is a four year old Windows 8.1 phone with non-replaceable Li-ion battery. The battery performance is not what it once was but still fairly decent. It will share Internet via Wi-Fi with my computer and I-pad for about 6 hours without a charge going from 100% to 20% in this period of time.
My question is this: I have a choice of using the battery in the fashion described above and then recharging after each 6 hours of use, or simply leave the charger plugged into the phone at all times when I'm using Internet-sharing and only using the battery when I use the phone as an actual mobile device. Which of these methods would be better for preserving as much battery life as I can?